All travelers to Mexico are required to present proof of citizenship, such as an original birth certificate with a raised seal, a valid passport, or naturalization papers. Those using a birth certificate should also have current photo identification, such as a driver’s license or official ID, such as a state or military issued ID. Driver’s licenses and permits, voter registration cards, affidavits and similar documents are not sufficient to prove citizenship for readmission into the United States. If the last name on the birth certificate is different from your current name, bring a photo identification card and legal proof of the name change, such as the original marriage license or certificate. Note: Photocopies are not acceptable.

Some U.S. citizens have encountered difficulty boarding flights in Mexico without a passport.

The Intelligence Reform and Terrorism Prevention Act of 2004 requires that by January 1, 2008, travelers to and from the Caribbean, Bermuda, Panama, Mexico, and Canada have a passport or other secure, accepted document to enter or re-enter the United States. As of press time, this requirement is scheduled to apply to all air and sea travel to or from Mexico, effective December 31, 2006.

Safeguard your passport in an inconspicuous, inaccessible place like a money belt, and keep a copy of the critical pages with your passport number in a separate place. If you lose your passport, visit the nearest consulate of your native country as soon as possible for a replacement.

For an up-to-date, country-by-country listing of passport requirements around the world, go to the “Foreign Entry Requirement” Web page of the U.S. State Department at http://travel.state.gov

Visas

You must carry a Mexican Tourist Permit (FMT), the equivalent of a tourist visa, which Mexican border officials issue, free of charge, after proof of citizenship is accepted. Airlines generally provide the necessary forms aboard your flight to Mexico. The FMT is more important than a passport, so guard it carefully. If you lose it, you may not be permitted to leave until you can replace it — a bureaucratic hassle that can take anywhere from a few hours to a week.

The FMT can be issued for up to 180 days. Sometimes officials don’t ask but just stamp a time limit, so be sure to say “6 months,” or at least twice as long as you intend to stay. If you decide to extend your stay, you may request that additional time be added to your FMT from an official immigration office in Mexico.

In Baja California, immigration laws have changed; they allow FMTs for a maximum of 180 days per year, with a maximum of 30 days per visit. This is to encourage regular visitors, or those who spend longer periods in Mexico, to obtain documents that denote partial residency.

For travelers entering Mexico by car at the border of Baja California, note that FMTs are issued only in Tijuana, Tecate, and Mexicali, as well as in Ensenada and Guerrero Negro. If you travel anywhere beyond the frontier zone without the FMT, you will be fined $40. Permits for driving a foreign-plated car in Mexico are available only in Tijuana, Ensenada, Tecate, Mexicali, and La Paz.

Note: Children under age 18 traveling without parents or with only one parent must have a notarized letter from the absent parent(s) authorizing the travel. Mexican law requires that any non-Mexican under the age of 18 departing Mexico must carry notarized written permission from any parent or guardian not traveling with the child. This permission must include the name of the parent, the name of the child, the name of anyone traveling with the child, and the notarized signature(s) of the absent parent(s). The child must carry the original letter (not a copy) as well as proof of the parent/child relationship (usually a birth certificate or court document), and an original custody decree, if applicable.

Customs

What You Can Bring into Mexico

When you enter Mexico, Customs officials will be tolerant as long as you have no illegal drugs or firearms. You’re allowed to bring in two cartons of cigarettes or 50 cigars, plus 1 kilogram (2.2 lb.) of smoking tobacco; two 1-liter bottles of wine or hard liquor, and 12 rolls of film. A laptop computer, camera equipment, and sports equipment that could feasibly be used during your stay are also allowed. The underlying guideline is: Don’t bring anything that looks as if it’s meant to be resold in Mexico.

What You Can Take Home from Mexico

Returning U.S. citizens who have been away for at least 48 hours are allowed to bring back, once every 30 days, $800 worth of merchandise duty-free. You’ll pay a flat rate of duty on the next $1,000 worth of purchases. Any dollar amount beyond that is subject to duties at whatever rates apply. On mailed gifts, the duty-free limit is $200. Be sure to keep your receipts or purchases accessible to expedite the declaration process. Note: If you owe duty, you are required to pay on your arrival in the United States — either by cash, personal check, government or traveler’s check, or money order (and, in some locations, a Visa or MasterCard).

To avoid paying duty on foreign-made personal items you owned before your trip, bring along a bill of sale, insurance policy, jeweler’s appraisal, or receipts of purchase. Or you can register items that can be readily identified by a permanently affixed serial number or marking — think laptop computers, cameras, and CD players — with Customs before you leave. Take the items to the nearest Customs office or register them with Customs at the airport from which you’re departing. You’ll receive, at no cost, a Certificate of Registration, which allows duty-free entry for the life of the item.

U.S. Citizens

For specifics on what you can bring back and the corresponding fees, download the invaluable free pamphlet Know Before You Go online at www.cbp.gov (click on “Travel,” and then click on “Know Before You Go! Online Brochure”). Or contact the U.S. Customs & Border Protection (CBP), 1300 Pennsylvania Ave. NW, Washington, DC 20229 (tel. 877/287-8667) and request the pamphlet.

Canadian Citizens

For a clear summary of Canadian rules, write for the booklet I Declare, issued by the Canada Border Services Agency (tel. 800/461-9999 in Canada, or 204/983-3500; www.cbsa-asfc.gc.ca).

A helpful brochure available from Australian consulates or Customs offices is Know Before You Go. For more information, call the Australian Customs Service at tel. 1300/363-263, or log on to www.customs.gov.au.

Most questions are answered in a free pamphlet available at New Zealand consulates and Customs offices: New Zealand Customs Guide for Travellers, Notice no. 4. For more information, contact New Zealand Customs, The Customhouse, 17-21 Whitmore St., Box 2218, Wellington (tel. 04/473-6099 or 0800/428-786; www.customs.govt.nz).

Going Through Customs

Mexican Customs inspection has been streamlined. At most points of entry, tourists are requested to press a button in front of what looks like a traffic signal, which alternates on touch between red and green. Green light and you go through without inspection; red light and your luggage or car may be inspected. If you have an unusual amount of luggage or an oversized piece, you may be subject to inspection anyway.